• Phonetics and Speech Sciences
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• v.13 no.2
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• pp.57-66
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• 2021

This study focuses on the issue of automatic severity classification of dysarthric speakers based on speech intelligibility. Speech intelligibility is a complex measure that is affected by the features of multiple speech dimensions. However, most previous studies are restricted to using features from a single speech dimension. To effectively capture the characteristics of the speech disorder, we extracted features of multiple speech dimensions: voice quality, prosody, and pronunciation. Voice quality consists of jitter, shimmer, Harmonic to Noise Ratio (HNR), number of voice breaks, and degree of voice breaks. Prosody includes speech rate (total duration, speech duration, speaking rate, articulation rate), pitch (F0 mean/std/min/max/med/25quartile/75 quartile), and rhythm (%V, deltas, Varcos, rPVIs, nPVIs). Pronunciation contains Percentage of Correct Phonemes (Percentage of Correct Consonants/Vowels/Total phonemes) and degree of vowel distortion (Vowel Space Area, Formant Centralized Ratio, Vowel Articulatory Index, F2-Ratio). Experiments were conducted using various feature combinations. The experimental results indicate that using features from all three speech dimensions gives the best result, with a 80.15 F1-score, compared to using features from just one or two speech dimensions. The result implies voice quality, prosody, and pronunciation features should all be considered in automatic severity classification of dysarthria.

• Speech Sciences
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• v.12 no.2
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• pp.121-128
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• 2005

This study was an attempt to determine acoustic characteristics in myna bird's notes. Two myna birds' sounds imitating a normal male voice in his late 20's were sampled and analyzed. The analyses included the mean values of F1, F2, F3 and pitch contours. The results were as follows; First, there was a significan difference in the mean values of F1, F2, and F3 in isolatd vowel /a/ and /i/ between the myna birds' sounds and the human voice. However, there was no apparent difference in pitch contour of their formants. Second, there was a difference in pitch contour of their formants in their sentence ('hn-nyung-ha-se-yo?' meaning 'How are you?') production. Namely, the myna birds' pitch contour was located higher than that of the human's.

• MALSORI
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• no.67
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• pp.33-60
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• 2008

The aim of this study is to show the differences in acoustic parameters between a pathological voice /a/ caused by vocal polyp and a normal voice /a/ produced after LMS (Laryngeal Microscopic Surgery). It was expected that voices of two kinds could be analyzed effectively in terms of HNR in specific frequency bands than in all frequency bands. For this study, 10 patients' voice were recorded before and after LMS and then were manipulated in terms of four acoustic parameter. It was found out that (a) frequency bands of 500Hz in the range of 1,000Hz to 4,000Hz were very useful to obtain HNR values; (b) frequency bands in the range of 1,248Hz to 5,500Hz on a log scale were very useful to obtain HNR values; (c) F0 dropped after LMS but not significantly; (d) the bandwidth of the second formant (B2) decreased significantly after LMS, while that of the first formant (B1) decreased after LMS but not significantly.

• Phonetics and Speech Sciences
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• v.6 no.4
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• pp.109-115
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• 2014

Fricated nuclei in Nuosu Yi were found to be more correctly described as fricated vowels, rather than syllabic fricatives due to the presence of clear formant structures typical of front vowels. In this exploratory study, two types of fricated nuclei were examined: retroflex "yr" and non-retroflex "y". The retroflex nucleus "yr" had higher F1 and lower F3 than non-retroflex "y", indicating a lower tongue height. On the other hand, F2 was found to correlate not with nucleus retroflexion, but instead with onset consonant retroflexion: F2 was higher following retroflex onsets, in both vowels. This effect was persistent through the entire vowel, suggesting a phonological effect, rather than a coarticulatory one. Interpretation of the F2 results require accompanying articulatory data since the usual coupling of F2 and tongue backness does not always hold for retroflex vowels. Examining the articulation of the fricated nuclei in Nuosu Yi is a direction for future research.

• Journal of the Korean Institute of Telematics and Electronics
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• v.25 no.12
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• pp.1503-1512
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• 1988

As the basic analysis to solve the within-and cross-speaker variability in phoneme based speech recognition, changes in pitch and formant frequencies of 8 Korean vowels with age and sex of speaker has been investigated by analyzing a large number fo samples. Conclusions obtained are as follows: 1) Changes in pitch frequency with age and sex of speaker for children are hard to distinguish and the difference of before and after the voice change is analyzed approximately 0.2 oct. for female an 0.9 oct. for male. 2) While most of the formants of vowel considerably change with the age of speaker, the change becomes smaller as the age becomes older. 3) While there is an indirect correlation between pitch and formant with change in age, it is hard to see a direct correlation. 4) When the objects of the recognition experiment by pitch and formants are various speakers in each age and sex, pitch also works as an efficient recognition parameter.

• Phonetics and Speech Sciences
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• v.9 no.4
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• pp.77-89
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• 2017

This study investigates the phonetic meaning of clarity and turbidity(淸濁) that has been used in psychoacoustics, musicology, and linguistics in both the East and the West. With a view to clarifying the phonetic meaning of clarity and turbidity, this study conducts three perception tests. First, 34 subjects were asked to take one of Clear and Turbid by forced choice for 5 pure and complex tones, respectively, ranging from A2 to A6 differing by octave. Second, they were asked to select between the two choices for 25 pure and complex tones, respectively, ranging from A2 to A4 differing by semitone. Third, they were asked to opt for one of the two choices for 8 different vowels of different formant and fundamental frequencies. Results showed that there is a certain range of tone which is perceived as clear, that clarity level increases as fundamental frequency increases, and that pure tones have a higher level of clarity than complex ones, fundamental frequency being equal. Results also showed that vocal tract resonance enhances clarity level on the whole, and that lower vowels have a higher level of clarity than higher ones. This study is significant in that it demonstrates that clarity level is proportional to fundamental frequency and the first formant frequency, all else being equal.

• Proceedings of the KOSOMBE Conference
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• v.1997 no.11
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• pp.67-70
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• 1997

In this paper, we evaluated the character of speech of hearing impaired person (HIP) who acquire his hearing loss after the youth. It is usually observed that severe HIP decreased not only speech perception but also vocalization. so there is a need for sensitive and quantitative measures or the assesment of the speech of the HIP to serve both diagnostic and prognosic purposes, 7 HIP and 12 normal hearing person(NHP) were studied with pure tone test and speaking test using word/sentence table which consists of vowel(a:), mono and two syllables and a sentence. we analyzed formant frequency, pitch, sound intensity, speech duration of HIP and NHP speech. According to the results, in the HIP's speech we find that formant frequency was shifted, first-formant prominence was reduced, the dynamic range of sound intensity was decreased, speech duration was prolonged. In the next, we expect the correlation between hearing and speech character of HIP is cleared through analysis of more acoustic parameters and precise selection of HIP group.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.9 no.1
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• pp.22-26
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• 1998

Uvulopalatopharyngoplasty(UPPP) is one of the most popular surgical procedure for the treatment of obstructive sleep apnea syndrome(OSAS) occurring at the level of oropharynx. However, voice changes after UPPP have been a challenging issue for the professional voice users, because even minor changes in voice quality or articulation may be critical to professional singers, teachers, and so on. Several acoustic changes after UPPP have been proposed. However, based on the authors understanding, there is no report about voice changes after UPPP in Korean. We measured the first, second and third formant frequencies of /a/, /i/, /u/ phonations in 20 adult male patients who had undergone UPPP surgery, and the nasalances of Rabbit, Baby, and Mama passages. These parameters were measured preoperatively, at 1 month and 3 months after the operation. Any subjective voice changes were asked to be reported at the posto-perative visits. The third formant(F3) of /u/ phonation was significantly reduced at postoperative 1 month measurement. The nasalance of Mama passage was singnificantly increased at postoperative 3 months measurement. No one complained of subjective changes in voice quality, timbre, articulation or speech. Even though there are no complaints about postoperative voice changes subjectively, significant changes in the formant characteristics of certain vowel and changes in the nasality after UPPP require the clinicians to be mort cautious and careful in deciding UPPP for the professional voice users.

• The Journal of the Korea Contents Association
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• v.13 no.9
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• pp.495-503
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• 2013

The purpose of this study was to investigate how Korean speakers produce English vowels. Twenty one Korean learners produced the vowels [i, ɪ, eɪ, ɛ, æ, ɑ, ʌ, ɔ, oʊ, ʊ, u] in bVt or pVt forms of real words. Acoustic measurements were conducted for the vowel formant frequencies (F1, F2) and duration. Results showed that Korean learners tended to produce the vowel duration longer than native English speakers. Also, the front vowels produced by Korean participants tended to be produced at the more frontal part of the tongue. In addition, Korean participants distinguished the tense and lax pairs not through quality(F1, F2) but through vowel duration. This is different from the native English speakers in that they differentiate tense and lax pairs by quality(F1, F2) as well as vowel duration. Based on these results, pedagogical implications are discussed.

• Phonetics and Speech Sciences
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• v.3 no.4
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• pp.45-53
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• 2011

Flemming and Johnson (2007) claim that there is a fundamental distinction between the mid central vowel [ə] and the high central vowel [?] in that [ə] occurs in an unstressed word-final position while [?] appears elsewhere. Compared to English counterparts, Korean [ə] and [?] are full vowels and they have phonemic contrast. The purpose of this paper is to explore the acoustic quality of two English reduced vowels produced by Korean learners and native speakers of English in terms of their two formant frequencies. Sixteen Korean learners of English and six native speakers of English produced four types of English words and two types of Korean words with different phonological and morphological patterns. The results show that Korean learners of English produced the two reduced vowels of English and their Korean counterparts differently in Korean and English words.